ATL: DORIAN - Post-Tropical - Discussion

[Aric Dunn]

:uarrow: Except for the fact that if it meets the criteria of a tropical cyclone, it should be classified as such at that time.

Best track can handle that.

Their job is to protect life and property, not please the weather enthusiasts

True but it should also be about being scientifically as accurate as possible.

[ozonepete]

Hasn't been a renumber yet. They're going to wait it looks like...

But often when it's delayed that means they are renumbering. Either way is fine with me.

[JonathanBelles]

I got an answer from Dr. Knabb himself regarding the 8pm motion questions:

@NHCDirector: @JonathanBelles Motion past several hours as described in TWO, which is also providing general motion next 2 days, not just current.

I'd still say it's a minor problem with that operation.

[TheStormExpert]

future may not be as dim as we were thinking unless there is another SAL surge. Models have less shear than they did 24 hours ago

Yeah but for Levi Cowan from Tropical Tidbits thinks it may not even survive the track across the MDR, due to colder SST's.

[SFLcane]

SPECIAL TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
1040 PM EDT TUE JUL 23 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

SATELLITE-DERIVED WIND DATA INDICATE THAT THE SURFACE LOW PRESSURE
SYSTEM LOCATED ABOUT 150 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS
IS PRODUCING WINDS TO NEAR GALE FORCE. HOWEVER...THE ASSOCIATED
THUNDERSTORM ACTIVITY REMAINS SOMEWHAT LIMITED AND HAS NOT YET BEEN
PERSISTENT ENOUGH FOR THE LOW TO BE DESIGNATED AS A TROPICAL
CYCLONE. IF THE THUNDERSTORMS INCREASE AND PERSIST...THEN THE LOW
COULD BECOME A TROPICAL DEPRESSION OR TROPICAL STORM ON WEDNESDAY
AS IT MOVES WEST-NORTHWESTWARD AT ABOUT 20 MPH. THIS SYSTEM HAS A
HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BERG

[ozonepete]

future may not be as dim as we were thinking unless there is another SAL surge. Models have less shear than they did 24 hours ago

Yeah but for Levi Cowan from Tropical Tidbits thinks it may not even survive the track across the MDR, due to colder SST's.

Ok, a lot of us really admire Levi (definitely including me) - he is one smart guy at this. But there are a number of us who disagree with him on that issue of SSTs. We will see.

[Alyono]

future may not be as dim as we were thinking unless there is another SAL surge. Models have less shear than they did 24 hours ago

Yeah but for Levi Cowan from Tropical Tidbits thinks it may not even survive the track across the MDR, due to colder SST's.

and he's not yet a met. I respect what he's doing, but he does not yet have the all of the background. His forecasts will get better, MUCH better, once he finishes his degree, however. Those final few courses make a tremendous difference in understanding the dynamics of the atmosphere.

He does have a very bright future ahead

[ozonepete]

SPECIAL TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
1040 PM EDT TUE JUL 23 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

SATELLITE-DERIVED WIND DATA INDICATE THAT THE SURFACE LOW PRESSURE
SYSTEM LOCATED ABOUT 150 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS
IS PRODUCING WINDS TO NEAR GALE FORCE. HOWEVER...THE ASSOCIATED
THUNDERSTORM ACTIVITY REMAINS SOMEWHAT LIMITED AND HAS NOT YET BEEN
PERSISTENT ENOUGH FOR THE LOW TO BE DESIGNATED AS A TROPICAL
CYCLONE. IF THE THUNDERSTORMS INCREASE AND PERSIST...THEN THE LOW
COULD BECOME A TROPICAL DEPRESSION OR TROPICAL STORM ON WEDNESDAY
AS IT MOVES WEST-NORTHWESTWARD AT ABOUT 20 MPH. THIS SYSTEM HAS A
HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BERG

Good call, Luis. They went with the persistence argument.

[TheStormExpert]

Yes, now one model has it over PR. See 98L models thread. Looks like the ridge will be strong to not allow an escape to fishland.

Do you think this could be a preview of whats to come later on this season, or is it too early to tell?

[TropicalAnalystwx13]

future may not be as dim as we were thinking unless there is another SAL surge. Models have less shear than they did 24 hours ago

Yeah but for Levi Cowan from Tropical Tidbits thinks it may not even survive the track across the MDR, due to colder SST's.

[NDG]

Deep convection continues on the SW quadrant of the LLC. If it persists through the night, if not by 2 AM by 5 AM I think it is finally going to be upgraded, IMO.

[Alyono]

a note about SST.

It is NOT SST itself that is the important factor. It is the difference between SST and upper trop temperature. If SST were all that mattered, then we wouldn't see late season genesis over sub 70F waters in the N Atl

[ozonepete]

future may not be as dim as we were thinking unless there is another SAL surge. Models have less shear than they did 24 hours ago

Yeah but for Levi Cowan from Tropical Tidbits thinks it may not even survive the track across the MDR, due to colder SST's.

Ha, welcome to the world of tropical cyclone forecasting. You so often have to produce a forecast chart and then hedge it with "well maybe not..." We all do it all of the time. If I had a dime for every time I did it...

[TheStormExpert]

Ok, a lot of us really admire Levi (definitely including me) - he is one smart guy at this. But there are a number of us who disagree with him on that issue of SSTs. We will see.

I really don't think they will be as big of a problem as the stable air it will experience in the coming days.

[ozonepete]

a note about SST.

It is NOT SST itself that is the important factor. It is the difference between SST and upper trop temperature. If SST were all that mattered, then we wouldn't see late season genesis over sub 70F waters in the N Atl

Yup. great point. The bigger the difference the steeper the lapse rates and then you can still easily get high enough thunderstorms. We've all seen this before.

[BigB0882]

Up to 70%. That almost guarantees an upgrade during the next TWO. According to the statistics, 100% of past storms to receive a 70% or higher chance for development have developed.

[CrazyC83]

I'm guessing if 98L was sitting near land, we would have a TD or TS right now. But they don't need to be too aggressive that far east.

[cycloneye]

Up to 70%. That almost guarantees an upgrade during the next TWO. According to the statistics, 100% of past storms to receive a 70% or higher chance for development have developed.

And here is in graphic.

[hurricanetrack]

Ok, I got one for you all, with 98L getting itself underneath a 600+dm ridge here in the next few days, why won't it be hauling its rear end to the west at like 30 mph? That is one powerful ridge and you would think the gradient would be such that the trades would be screaming. I suppose it is far enough north for this not to matter as much? That struck me as a possible reason why this would get killed off: moving too fast. But - perhaps not? What say you?

[NDG]

Ok, I got one for you all, with 98L getting itself underneath a 600+dm ridge here in the next few days, why won't it be hauling its rear end to the west at like 30 mph? That is one powerful ridge and you would think the gradient would be such that the trades would be screaming. I suppose it is far enough north for this not to matter as much? That struck me as a possible reason why this would get killed off: moving too fast. But - perhaps not? What say you?

Is not so much winds at H50 is at near H85, which I only see winds near 15-20 knots in front and behind 98L, so the low level jet is not going to be no where as strong as it was with Chantal.